Nah, it was Scheme plus (a stripped-down) CLOS. A possible point of confusion was that the development environment, including the CPS Scheme compoiler, was written in Common Lisp. Also, all values were instances of (mini-CLOS) classes.

Wow. Did it have call/cc? No special variables? I would have sworn it was based on CL when I played with it back when I was a customer while you guys were building it in MCL. But I was mostly using the object system.

The Dylan team consciously chose not to provide call/cc. It had a restricted form of call/cc called "bind-exit" that supported only upward continuations.

It didn't have special variables, but it did have module variables, which were lexically accessible from anywhere inside the module where they were defined, or in any module that imported them. THey were more like entries in Smalltalk dictionaries than special variables (a possibly-overlooked point is that the initial design discussions at Apple included several Smalltalk enthusiasts from ATG).

The object system would definitely have looked like Common Lisp. It was CLOS minus some of the bells and whistles, as you observed.

Also, like Scheme and unlike Common Lisp, Dylan was a Lisp-1, not a Lisp-2.

For those unfamiliar with that jargon, it refers to how namespaces are organized in Lisps. In Dylan, as in Scheme, there was a single namespace for variables, functions, types, and so on. For example, <collection> was the abstract superclass of all collections, but the name "<collection>" was just a read-only module variable that happened to refer to the (anonymous) class.

By contrast, in Common Lisp there are separate namespaces for variables, functions, classes, and some other things. Thus, in Common Lisp (but not in a Lisp-1), you can have a function named "address", a class named "address", and a lexical variable named "address", and they don't collide or shadow one another.